1. Field of the Invention
The invention is directed to an object support column with a vertical tube, a base part arranged at a first end of the vertical tube, a guide bush fastened to a second end of the vertical tube opposite the base part, a telescope tube arranged coaxially in the vertical tube that is movable along a center longitudinal axis in the guide bush, a pressure tube of a gas spring filled with a compressed gas, a guide tube arranged in the pressure tube, a piston guided in the guide tube that divides the pressure tube into a first work chamber and a second work chamber, a piston rod fastened by one end to the piston extends through the second work chamber guided outward to be sealed by a sealing and guiding device at a first end of the pressure tube and is arranged with its other end at the base part of the vertical tube, and a flow connection between the first work chamber and the second work chamber that can be shut off by a valve actuated by an actuating device.
2. Description of the Related Art
A generic object support column of this kind is known from DE 34 20 528 C2.
However, a disadvantage in object support columns is that they do not allow the load to be detected and, therefore, do not make it possible to adapt a chair mechanism to the weight of an occupant of the chair. A chair mechanism adapted to the weight of the occupant of the chair, for example, when the backrest is preloaded, would be desirable for keeping up with the demands of chair users with respect to comfort, which have increased since the prior art.
A solution is suggested in DE 10 2006 027 987 B3. The object support column presented therein comprises a gas spring with a first piston rod for length adjustment and a second piston rod for load detection of the gas spring. The second piston rod cooperates with a force accumulator which generates a preloading force on the second piston rod. The preloading force generated by the force accumulator prevents the second piston rod from being pushed out in the unloaded state of the gas spring and acts as a defined opposing force for the push-out force acting on the second piston rod in the loaded state of the gas spring. The second piston rod is pushed out of the housing in a defined manner against the preloading force in the loaded state when, for example, a chair user sits on a chair outfitted with the gas spring. The push-out path of the second piston rod is a measure of the loading of the gas spring, and the push-out movement serves at the same time for the mechanical adaptation of the chair mechanism.
Aside from the large installation space that is required, it is disadvantageous that information about the loading of the object support column and about the weight of the user of the chair is detected either incompletely or not at all depending on the stroke position. When the piston rod is completely pushed into the pressure tube of the gas spring, the end of the pressure tube on the piston rod side comes into contact with a stop buffer. A further deflection of the gas spring is no longer possible and the work chamber between the piston of the first piston rod and the piston of the second piston rod cannot be subjected to compression. Accordingly, the second piston rod cannot be moved out any farther so that information about the loading of the gas spring in turn is not detected and cannot be passed into the seat mechanism.
The seat loading of the gas spring by a determined weight force can be associated with a definite spring stroke. When the gas spring is in a position in which the stroke range which is still available is less than the spring stroke associated with the determined weight force, the spring stroke can no longer be realized in its entirety so that information about the loading of the gas spring is erroneously detected and cannot be correctly conveyed to the seat mechanism.